text: /*
   * Copyright 2000, International Business Machines Corporation and others.
   * All Rights Reserved.
   * 
   * This software has been released under the terms of the IBM Public
   * License.  For details, see the LICENSE file in the top-level source
   * directory or online at http://www.openafs.org/dl/license10.html
   */
  
  #include <afsconfig.h>
  #include "afs/param.h"
  
  
  #include "afs/sysincludes.h"	/* Standard vendor system headers */
  #include "afsincludes.h"	/* Afs-based standard headers */
  #include "afs/afs_stats.h"	/* afs statistics */
  #include "osi_compat.h"
  
  static char waitV, dummyV;
  
  void
  afs_osi_InitWaitHandle(struct afs_osi_WaitHandle *achandle)
  {
      AFS_STATCNT(osi_InitWaitHandle);
      achandle->proc = (caddr_t) 0;
  }
  
  /* cancel osi_Wait */
  void
  afs_osi_CancelWait(struct afs_osi_WaitHandle *achandle)
  {
      caddr_t proc;
  
      AFS_STATCNT(osi_CancelWait);
      proc = achandle->proc;
      if (proc == 0)
  	return;
      achandle->proc = (caddr_t) 0;	/* so dude can figure out he was signalled */
      afs_osi_Wakeup(&waitV);
  }
  
  /* afs_osi_Wait
   * Waits for data on ahandle, or ams ms later.  ahandle may be null.
   * Returns 0 if timeout and EINTR if signalled.
   */
  int
  afs_osi_Wait(afs_int32 ams, struct afs_osi_WaitHandle *ahandle, int aintok)
  {
      afs_int32 endTime;
      int code;
  
      AFS_STATCNT(osi_Wait);
      endTime = osi_Time() + (ams / 1000);
      if (ahandle)
  	ahandle->proc = (caddr_t) current;
  
      do {
  	AFS_ASSERT_GLOCK();
  	code = afs_osi_TimedSleep(&waitV, ams, 1);
  	if (code)
  	    break;
  	if (ahandle && (ahandle->proc == (caddr_t) 0)) {
  	    /* we've been signalled */
  	    break;
  	}
      } while (osi_Time() < endTime);
      return code;
  }
  
  afs_event_t *afs_evhasht[AFS_EVHASHSIZE];	/* Hash table for events */
  #define afs_evhash(event)	(afs_uint32) ((((long)event)>>2) & (AFS_EVHASHSIZE-1))
  int afs_evhashcnt = 0;
  
  /* Get and initialize event structure corresponding to lwp event (i.e. address)
   * */
  static afs_event_t *
  afs_getevent(char *event)
  {
      afs_event_t *evp, *newp = 0;
      int hashcode;
  
      AFS_ASSERT_GLOCK();
      hashcode = afs_evhash(event);
      evp = afs_evhasht[hashcode];
      while (evp) {
  	if (evp->event == event) {
  	    evp->refcount++;
  	    return evp;
  	}
  	if (evp->refcount == 0)
  	    newp = evp;
  	evp = evp->next;
      }
      if (!newp)
  	return NULL;
  
      newp->event = event;
      newp->refcount = 1;
      return newp;
  }
  
  /* afs_addevent -- allocates a new event for the address.  It isn't returned;
   *     instead, afs_getevent should be called again.  Thus, the real effect of
   *     this routine is to add another event to the hash bucket for this
   *     address.
   *
   * Locks:
   *     Called with GLOCK held.
   */
  
  static void
  afs_addevent(char *event)
  {
      int hashcode;
      afs_event_t *newp;
  
      AFS_ASSERT_GLOCK();
      hashcode = afs_evhash(event);
      newp = kzalloc(sizeof(afs_event_t), GFP_NOFS);
      afs_evhashcnt++;
      newp->next = afs_evhasht[hashcode];
      afs_evhasht[hashcode] = newp;
      init_waitqueue_head(&newp->cond);
      newp->event = &dummyV;	/* Dummy address for new events */
  }
  
  #ifndef set_current_state
  #define set_current_state(x)            current->state = (x)
  #endif
  
  /* Release the specified event */
  #define relevent(evp) ((evp)->refcount--)
  
  /* afs_osi_SleepSig
   *
   * Waits for an event to be notified, returning early if a signal
   * is received.  Returns EINTR if signaled, and 0 otherwise.
   */
  int
  afs_osi_SleepSig(void *event)
  {
      struct afs_event *evp;
      int seq;
      int code;
  
      evp = afs_getevent(event);
      if (!evp) {
  	afs_addevent(event);
  	evp = afs_getevent(event);
      }
  
      seq = evp->seq;
  
      AFS_GUNLOCK();
      code = wait_event_freezable(evp->cond, seq != evp->seq);
      AFS_GLOCK();
  
      if (code == -ERESTARTSYS)
  	code = EINTR;
      else
  	code = -code;
  
      relevent(evp);
      return code;
  }
  
  /* afs_osi_Sleep -- waits for an event to be notified, ignoring signals.
   * - NOTE: that on Linux, there are circumstances in which TASK_INTERRUPTIBLE
   *   can wake up, even if all signals are blocked
   * - TODO: handle signals correctly by passing an indication back to the
   *   caller that the wait has been interrupted and the stack should be cleaned
   *   up preparatory to signal delivery
   */
  void
  afs_osi_Sleep(void *event)
  {
      sigset_t saved_set;
  
      SIG_LOCK(current);
      saved_set = current->blocked;
      sigfillset(&current->blocked);
      RECALC_SIGPENDING(current);
      SIG_UNLOCK(current);
  
      afs_osi_SleepSig(event);
  
      SIG_LOCK(current);
      current->blocked = saved_set;
      RECALC_SIGPENDING(current);
      SIG_UNLOCK(current);
  }
  
  /* afs_osi_TimedSleep
   * 
   * Arguments:
   * event - event to sleep on
   * ams --- max sleep time in milliseconds
   * aintok - 1 if should sleep interruptibly
   *
   * Returns 0 if timeout, EINTR if signalled, and EGAIN if it might
   * have raced.
   */
  int
  afs_osi_TimedSleep(void *event, afs_int32 ams, int aintok)
  {
      int code = 0;
      long ticks = (ams * HZ / 1000) + 1;
      struct afs_event *evp;
      int seq;
  
      evp = afs_getevent(event);
      if (!evp) {
  	afs_addevent(event);
  	evp = afs_getevent(event);
      }
  
      seq = evp->seq;
  
      AFS_GUNLOCK();
      code = wait_event_freezable_timeout(evp->cond, evp->seq != seq, ticks);
      AFS_GLOCK();
      if (code == -ERESTARTSYS)
  	code = EINTR;
      else
  	code = -code;
  
      relevent(evp);
  
      return code;
  }
  
  
  int
  afs_osi_Wakeup(void *event)
  {
      int ret = 2;
      struct afs_event *evp;
  
      evp = afs_getevent(event);
      if (!evp)			/* No sleepers */
  	return 1;
  
      if (evp->refcount > 1) {
  	evp->seq++;
  	wake_up(&evp->cond);
  	ret = 0;
      }
      relevent(evp);
      return ret;
  }
  